It has long been desirable to produce coated cookware which has an inner cooking surface having good release properties while exhibiting good abrasion resistance. It is also desirable that heat can be rapidly transferred to such cooking surfaces without the need to subject the outer bottom surface of the cooking vessel to excessive heat. Cookware with a release coating that includes a heat conductive pattern that enhances heat transfer to and evenly distributes heat about the cooking surface is disclosed in U.S. Pat. No. 6,114,028 to Muchin et al. The heat conductive pattern in Muchin is arranged such that it extends outwardly from the central region of the inner surface of a cooking vessel toward the outer peripheral region. This facilitates transfer of heat from the central region to the outer region and assists in maintaining the entire cooking surface at a uniform temperature, especially if the cooking vessel is placed on a heating element that has a smaller diameter than the diameter of the vessel's bottom.
However, as discussed in U.S. Pat. No. 6,248,435 to Leck, it is common to expose cookware to heating over the entire flat surface of the cookware. Leck thus provides an improved heat transfer release finish on cookware by coating the cookware interior with a mixture of fluoropolymer and magnetic flakes, such as stainless steel, and magnetically orienting the flakes to run in the thickness direction of the coating.
However, both of the above mentioned patents rely on magnetically orienting flake to achieve enhanced thermal properties of the release coatings disclosed. The requirement to magnetically induce orientation of the flake necessitates special equipment that can hamper the efficient commercial production of the cookware.
Recent inventions recognize the advantage of adding an inorganic filler film hardener component to the undercoat of multilayer nonstick coatings. Leck, U.S. Pat. No. 6,248,435, discloses that this component may be one or more metal silicate compounds such as aluminum silicate and metal oxides, such as titanium dioxide and aluminum oxide. Thomas, U.S. Pat. No. 6,291,054, and Tannenbaum, U.S. Pat. No. 6,761,964 A1 disclose the advantage of reinforcing the undercoat with particles of silicon carbide for superior abrasion resistance. It would be desirable to provide cookware which has even better heat transfer properties than those exhibited by the prior art to allow the cookware to heat up even faster and exhibit good or improved abrasion resistance while maintaining good release characteristics.